(with apologies to Douglas Adams)
Suppose you want to make a reservation at The Restaurant at the End of the Ecosphere, one of the most exclusive destinations in the entire universe.
This is not an undertaking for the faint-hearted. To have a chance of booking your place to witness the mass extinction to end all mass extinctions — an event that will exterminate at least 10 million species of complex multicellular life-forms — you’ll need perseverance on a truly superhuman scale.
That means patience, and plenty of it. You must be prepared for the long haul, roughly eight billion years from the Big Bang just to get onto the waiting list. That’s because your best chance of observing the extermination of 10 million species of complex life-forms is to find somewhere with more than 10 million. For that you’re going to need a galaxy. Well, there’s no shortage of those, but you’ll want one with a well-behaved middleweight star situated in a relatively uneventful region of that galaxy. There are plenty of those as well, but yours will need a good sprinkling of cosmic detritus, such as carbon, nitrogen, oxygen, silicon and iron, to be spilled out into rocky planets while it forms. That requires waiting till a steady supply of supernovae have blasted such stuff into space before your star gets born. Not forgetting a sprinkling of radioactive elements, because your planet will need a nice hot core that doesn’t cool down too fast. Hence the long wait.
And the wait doesn’t end there. You’re going to have to find a planet that keeps liquid water on its surface for several billion years, give or take a couple of snowball eras when the water has to lurk under a planet-wide ice sheet. That means your planet will need plenty of methane and carbon dioxide in the atmosphere at first, while its young sun is working towards full brightness, plus a way of extracting the methane after about a billion years, and then gradually drawing down most of the carbon dioxide, starting after about another billion years, as that sun heats up.
Read more: Resilience